Supplementary Information - Results of Operations from Oil and Gas Producing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Oil and gas sales	$ 84,015	$ 93,215
Costs and Expenses:
Lease operating expenses	33,461	34,996
Depreciation, depletion and accretion	34,616	36,154
Income tax expense	1,421	3,724
Total Costs and Expenses	69,498	74,874
Results of Operations from Producing Activities (excluding corporate overhead and interest costs)	$ 14,517	$ 18,341